Electro Oxidation Wastewater Treatment

We discussed about the mechanisms of electro oxidation wastewater treatment processes, by explaining direct and indirect oxidation, and how these two mechanisms enhance the comprehensive capability and efficiency when it comes refractory organic compounds mineralization and eventually complete removal within the previous section.                                                                                                                                                                                                                                                                                                                                                                                                                                                                   In this part, we will cover main factors affect electro oxidation wastewater treatment efficiency, mainly based on our years of experiences with electro oxidation treatablity test, wastewater treatment product research and development processes, and implement of electro oxidation wastewater treatment products, from trial scale, to pilot scale industrial wastewater treatment projects.                                                                                                                                                                                                                                                                                                                                                                          Check the key points affect electro oxidation wastewater treatment efficiency we listed below:  

Electrode materials:                                                                                                                                                                                                                                        People in water and wastewater treatment industry and electrochemical research niche have adopted a vast variety of electrode materials for electro oxidation wastewater treatment processes, factors such as:                                                                                                                                                                                                                                                                                                                                                                                                                                          Capability of electrochemical generation of oxidizing agents, which affects the comprehensive organic compounds removal efficiency as different electrode has different surface property and electro-catalytic activity.                                                                                                                                                                                                                                                                                                                                                                                                                                          Chemical and mechanical robust, electrodes with stable chemical and mechanical stability can emit constant and stable performance within the electrolytic processes, and that means less chance of fouling.                                                                                                                                                                                                                                                                                                                                                                                                                                                    Stainless steel, platinum, lead dioxide (PbO2), mixed metal oxide(MMO), titanium, and boron-doped diamond (BDD) electrodes and etc, are adopted to conduct electro oxidation wastewater treatment, we will resume dicussions about comparison of different electrode materials in electro oxidation application in other contents.

Surface area:                                                                                                                                                                                                                                                            Actually electro oxidation reaction efficiency will be affected by the surface area of an electrode, as active area of electrodes, electron transfer, and larger surface area means enhanced electro oxidation of refractory organic compounds within the electrolyte (wastewater), therefore improve the comprehensive oxidation efficiency, yes, as you may have noticed from the previous section, surface area is one of those factors impact direct and indirect oxidation. . 

Wastewater compositions:                                                                                                                                                                                                                        Characteristics such as oxidation potentials, potential to be degraded into intermediates, or inorganic matters, are different amongst different type of organic pollutants, and ions in the waste streams might affect the conductivity of the electrolytes, therefore it’s critical to conduct treatability testing prior to electro oxidation technology implement in actual wastewater treatment, that is to identify the content of the wastewater you need treat, via electro oxidation.

pH level:                                                                                                                                                                                                                                                         Hydroxyl radicals are the major group of reactive oxygen species mineralize organic compounds within the electro oxidation processes, and yes, pH level within the electrolyte (wastewater) does affect the electrochemical generation of these active oxidizing agents on the surface of anode, as hydroxyl radicals will be more prevailing in alkaline conditions, according to our tests. 

Current density:                                                                                                                                                                                                                                              Current density reflects the mass transfer of electron, which means current density could actually affect the efficiency of direct oxidation, transfer of electrode, therefore it’s critical to keep some mediate current density to expedited oxidation reaction rate, but yet, minimize chances of undesired oxygen evolution, that is the key to constant electro generation of reactive oxygen species.

Electrochemical Cell Design:                                                                                                                                                                                                                                   Electrochemical cells are critical when it comes to implements of electro oxidation wastewater treatment processes, as electrochemical cells are the main spaces for electrolytic processes, and distance between electrodes, active electrode surface area, cell holding space, flow rate, initial COD level, hydraulic retention time, and COD removal efficiency.